Here is a summery of the edition changes in Windows 7:
* Windows Vista's Starter has been renamed to Home Basic for Windows 7.
Like the Windows XP and Windows Vista Starter Editions, this one is going to be released only "in emerging markets such as Brazil, People's Republic of China, India, Indonesia, Mexico, Pakistan, the Philippines, and Thailand."
* Windows Vista's Home Basic has been renamed to Starter for Windows 7.
It's "An option for "folks that will do very limited things with their PCs", with limitations: the Aero Glass theme is not included, it will only be sold in a 32-bit edition, and the system is limited to running only three applications simultaneously."
Which as hard as it is for geeks to believe there actually are people who barely use a computer at all :D
So this edition would be a great option for them.
* Windows Vista Home Premium and Windows 7 Home Premium have the same features.
They have the following advantages over Windows XP's editions:
It contains features from Windows XP Home Edition, Windows XP Media Center Edition, Windows XP Tablet PC Edition and Windows XP Professional x64 Edition.
* The Business Edition is gone and Professional has been added with the features available in the following previous editions:
Windows XP Home Edition, Professional Edition, Media Center Edition, Tablet PC Edition and Professional x64 Edition.
Windows Vista Home Premium, Business Edition.
Selected features from Windows Vista Ultimate like "Join a Windows Server domain, Use Remote Desktop, location aware printing, Encrypting File System, and Presentation Mode."
* Windows Vista's Enterprise and Enterprise for Windows 7 are the same.
"This edition targets the enterprise segment of the market and will be sold through volume licensing."
* Windows Vista's Ultimate has been removed and Ultimate for Windows 7 added.
"Windows 7 Ultimate contains the same features as Enterprise, but unlike that edition will be available to home users on an individual license basis. Unlike Windows Vista Ultimate, the Windows 7 Ultimate edition will not include the Windows Ultimate Extras feature or any exclusive features"
You can read all the information about changes from Windows XP Editions to Windows Vista and then to Windows 7 by reading the information at:
Wikipedia - Windows XP Editions
Wikipedia - Windows Vista Editions
Wikipedia - Windows 7 Editions